Engine speed control system

ABSTRACT

An engine speed control system for a vehicle such as a go-kart in order to, independently of the driver, control the speed of the vehicle includes a butterfly valve which is moved by a stepper motor ( 70 ) upon receipt of over the air signals by a receiver ( 60 ) from a control station ( 50 ). The movement of the butterfly valve alters the amount of air and fuel drawn into the engine independent of control of a throttle assembly ( 22, 25 ) operated by the driver of the vehicle. Thus, the vehicle can be slowed from a control station ( 50 ) independently of the vehicle if necessary.

[0001] This invention relates to an engine speed control system and toan engine having such a system. The invention has particular applicationto go-karts but could be used in other environments if desired.

[0002] Go-kart racing is a popular pass time. Go-kart tracks for noviceriders are quite common and enable novice drivers to race go-karts forfun or to compete in races either on an individual basis or in groups.Generally, to participate in go-kart racing at this level no speciallicence is required. One problem which does occasionally occur withnovice drivers is that such drivers may attempt to drive beyond theiralibility or, may simply drive in an uncourteous or dangers manner.

[0003] Presently, there is a system which enables an operator to controlthe speed of go-karts on a track and this system involves the remoteretarding of the electric system of the vehicle so as to cause somelimited speed control over the vehicle. This system does thereforeprovide some limited control whereby an operator can reduce the speed ofa go-kart should that be necessary but has the disadvantage that thechanging of the electric timing of the vehicle causes incompletecombustion of fuel and therefore has a polluting effect.

[0004] The object of the present invention is to provide an enginecontrol system which does not depend on a change of the ignition timingof the vehicle to slow the vehicle and therefore does not have thepolluting effect of the prior art system.

[0005] The invention, in a first aspect, may be said to reside in anengine speed system for a vehicle having an engine, a fuel and airsupply system for supplying air and fuel to the vehicle, and driveractuable means for controlling the supply of air and fuel so as toenable the speed of the vehicle to be increased or decreased by thedriver of the vehicle, said system including;

[0006] a valve unit for selectively allowing, preventing or reducing thesupply of air and fuel to the engine;

[0007] control means for moving the valve to alter the amount of fueland air supplied to the vehicle to thereby change the speed of thevehicle independent of the driver actuable means; and

[0008] receiver means for receiving a transmitted signal to cause thecontrol means to move the valve unit for changing the speed of theengine independent of the driver.

[0009] Since the system includes a valve which alters the flow of airand fuel to the engine, the valve operates in the same manner as acarburettor or fuel supply system and thereby, independent of thedriver, changes the speed of the vehicle in the same manner as acarburettor or other fuel and air supply system. Thus, the speed ischanged without changing the ignition timing of the vehicle andtherefore does not have the polluting effects of the prior art system.

[0010] Preferably the system includes a support member, the supportmember having an opening through which air and fuel can be supplied,said valve comprising a butterfly valve which is moveable in a linearmanner so as to close the opening to a desired degree between a firstposition allowing maximum supply of air and fuel to the engine and asecond position allowing minimum or no supply of air or fuel to theengine.

[0011] Preferably the control means comprises a stepper motor having astepper motor shaft connected to the butterfly valve so that uponactuation of the stepper motor the shaft is moved to in turn move thebutterfly valve between the fist and second positions.

[0012] Preferably the receiving means comprises a receiver and steppermotor controller for actuating the stepper motor to cause the butterflyvalve to move between the first and second positions.

[0013] Preferably the system includes a transmitter for transmitting thetransmitted signal to the receiver for detection by the receiver and foroperating the stepper motor.

[0014] Preferably the transmitter is coupled to a computer for receivingoperator inputs to cause the transmitter to transmit the transmittedsignal.

[0015] In other embodiments of the invention the control means mayinclude a servo-motor, or other electric motor, a cable control systemfor moving the valve or an air operated device for moving the valve.

[0016] In other embodiments the valve may be rotatable from an openposition to a closed position rather than linearly moveable from an openposition to a closed position. In other embodiments the butterfly valvemay be moved be a lever arrangement acting through a fulcrum.

[0017] The invention may also be said to reside in an engine for avehicle including;

[0018] a fuel and air supply system for supplying air and fuel to theengine;

[0019] a driver controlled throttle for controlling the fuel and airsupply system for altering the speed of the engine;

[0020] a valve unit for selectively allowing, preventing or reducing thesupply of air and fuel to the engine;

[0021] control means for moving the valve to alter the amount of fueland air supplied to the vehicle to thereby change the speed of thevehicle independently of the driver; and

[0022] receiver means for receiving a transmitted signal to cause thecontrol means to move the valve for changing the speed of the engineindependent of the driver.

[0023] Preferably the fuel and air supply means comprises a carburettorincluding a primary butterfly valve.

[0024] Preferably the valve unit includes a secondary butterfly valve.

[0025] The invention may also be said to reside in a method ofcontrolling the speed of a vehicle on a driveway which is being drivenby a driver, the method including the steps of;

[0026] transmitting a signal to the vehicle from a remote location byway of wireless transmission; and

[0027] causing, by way of the transmission, the closing of a valvemember independent of driver control, so as to reduce, increase or shutoff supply of air and fuel to a vehicle of the engine, and whereby, thespeed of the engine is thereby altered by the transmitted signal.

[0028] A preferred embodiment of the invention will be described, by wayof example with reference to the accompanying drawings in which;

[0029]FIG. 1 is a schematic view of one embodiment of the invention;

[0030]FIG. 2 is a cross-sectional view through the main component of thepreferred embodiment; and

[0031]FIG. 3 is a plan view of the components shown in FIG. 2.

[0032] With reference to FIG. 1 the engine control system of theinvention is primarily intended for use with small capacity enginesschematically represented by block 20 which may be one or two cylinderengines typically used in go-karts or like vehicles. Fuel and air issupplied to the engine 20 by a carburettor 22 in a conventional manner.However, rather than use a carburettor 22 fuel and air may be suppliedby an injection system or the like. In conventional engines used ingo-kart racing the carburettor 22 is separated from the engine by aspacer. The spacer, spaces the carburettor 22 from the engine 20, andalso provides some insulation to prevent heat transfer into thecarburettor 22 which may otherwise cause premature evaporation of fuelwithin the carburettor 22 thereby impairing operation of thecarburettor.

[0033] The preferred embodiment of the present invention includes asupport member 30 which can take the place of the spacer and which, ifdesired, can have the same shape as the spacer. Thus, the support memberhas the same function as the spacer to space the carburettor 22 from theengine 20 and also insulate the carburettor to some extent to preventevaporation of fuel.

[0034] The support member 30 will be described in more detail withreference to FIGS. 2 and 3.

[0035] In normal operation of a vehicle such as a go-kart the driverwill depress an accelerator pedal (not shown) to control primarybutterfly valve 25 of the carburettor 22 to control the supply of airand fuel to the engine 20 to thereby control the speed of the engine 20.

[0036] The system of the preferred embodiment of the invention enablesthe speed of the engine 20 to be altered independent of the driver sothat if desired, the speed of the vehicle can be reduced if the driveris driving at the speed beyond his or her capacity or driving in adangerous or reckless manner. Alternatively, the speed can be increasedif desired as will be explained in more detail hereinafter.

[0037] In order to alter the speed of vehicle independent of the driver,an operator is supplied with a computer 50 which couples to wirelesstransmitter 52. The computer 50 can store information relating to eachof the vehicles and also can receive input data relating to the driverof the vehicles such as weight, and other perimeters indicative of thedrivers ability. Each vehicle fitted with a system according to thepresent invention is controlled by a transmitted signal from thetransmitter 52 of a different frequency which is received by a receiver60 within the vehicle. The receiver 60 is powered by power wires 62 froma battery (not shown) or from a generator or alternator within thevehicle. The receiver 60 includes a stepper motor controller 62 or iscoupled to a stepper motor controller 62 which is connected to a steppermotor 70 by lines 72. The stepper motor 70 is preferably mounted on thesupport member 30 as will be described in more detail with reference toFIG. 3.

[0038] The operator can initially set the maximum speed of the vehicleby causing the transmitter 52 to output a signal to the receiver 60 tocause the receiver 60, via the stepper motor controller 62, to controlthe stepper motor 70 to adjust the system to limit the maximum speed ofthe vehicle to a predetermined level. If during the course of drivingthe driver is driving recklessly or obviously driving at a speed whichis beyond his ability, the speed can be reduced by the operator inputting an appropriate input into the computer 50 indicative of thevehicle concerned so that an output signal is transmitted from thetransmitter 52 and received by the receiver 60 of the vehicle concernedso that the stepper motor 70 can be adjusted to reduce the maximum speedof the vehicle or to stop the vehicle completely.

[0039] The support member 30 is shown in FIGS. 2 and 3 and comprises afrustro-conical shaped end portion 32 which has a substantially flatplate portion 34 extending outwardly therefrom. The plate 34 has anopening 36 which may be circular in cross section which aligns with thecarburettor 22 and the inlet to the engine 20 when the support member 30is mounted on the engine 20. The support member 30 may be mounted inplace by bolts 33 shown in FIG. 3. The plate 34 is provided with arecess or grooved section 37 and the section 37 communicates with a bore38 provided in the frustro-chronicle portion 32. A butterfly valve 71 isprovided within the recess 37 and is bolted to a butterfly shaft 72 byscrews or bolts 74. The shaft 74 has a bore 76 which has an internalscrew thread for connection to a screw threaded stepper motor shaft 80of the stepper motor 70. The stepper motor 70 is attached to end wall 85of the frustro-chronicle portion 32.

[0040] Thus, when the stepper motor 70 is actuated the stepper motorshaft 80 moves in linear fashion in the direction of double headed arrowA in FIGS. 2 and 3 so as to move the butterfly valve 70 in the samedirection so that the butterfly valve can completely open the opening 36or alternatively completely close the opening 36 or close the opening 36to a partial extent.

[0041] The support member 30 is closed by an insulating plate 88 whichprovides insulation to the support member 30 and also to the carburettor22. The plate 88 also provides an interior surface 90 on which thebutterfly valve 71 can slide from its first position in which theopening 36 is completely open to its second position where the opening36 is completely closed.

[0042] Thus, as previously mentioned, in order to limit the speed of thevehicle or completely stop the vehicle, the stepper motor 70 iscontrolled via the transmitter 52, the receiver 60 and the stepper motorcontroller 62 so as to cause the stepper motor shaft 80 to move in thedirection of double headed arrow A to adjust the position of thebutterfly valve 71 relative to the opening 36. If it is desired to slowthe vehicle, the opening 36 is closed to a greater extent via thebutterfly valve 71, or if it is desired to completely stop the vehiclethe butterfly valve 71 is moved so that it completely closes the opening36 to shut off the supply of air and fuel to the vehicle completely.

[0043] The butterfly valve 70 may be formed from metal, such asaluminium, or plastics material. The frustro-conical section 32 andplate section 34 of the support member 30 are preferably formed frommetal such as aluminium.

[0044] As shown in FIG. 3 the plate member 34 may include a flange orancillary plate section 95 which provides for additional cowling overthe motor 20 to guide air flow over the motor or to support cabling suchas spark plug leads or other engine components.

[0045] As has previously been made clear, the system according to thepresent invention therefore enables an operator, from a remote position,to control the speed of a vehicle in the event of dangerous driving orif it is apparent that a driver is driving beyond his or her capacity.Furthermore, the initial speed limit of the vehicle can be set forhandicapping purposes for novice racing so as to limit the speed of somevehicles relative to others dependant on the weight of the driver, theability of the driver or other perimeters.

[0046] The computer 50 may have stored in it appropriate date relatingto a frequency of the transmitted signal applicable to each of thevehicles and data relating to each of the vehicles so that the vehiclescan be identified and appropriate inputs made into the computer 50 tocause appropriate signals to be transmitted by the transmitter 52 tocontrol the speed of the required vehicles. The input may be by way ofkeyboard or touch screen or the like.

[0047] Whilst the preferred embodiment has been described with referenceto controlling the butterfly valve for linear movement by a steppermotor, the valve could be a rotary valve or other moveable valvecontrolled by some other mechanism such as other types of motors or, anair operated device such as an air ram or cylinder, or a cable systemwhich causes winding in of a cable or the reeling out of a cable tocause the valve 71 to move to close or partially close the opening 36.

[0048] Normal fuel compatible gasket material may also be disposedbetween the support member 30 and the engine 20 and the carburettor 22if desired. The stepper motor shaft 80 may be sealed within the bore 38by a tube or pilot guide (not shown) or by a suitable seal so as toprevent the ingress of air through the bore 76.

[0049] In still further embodiments, rather than provide a stepper motorwhich has a stepper shaft arranged for linear movement, the steppermotor may have a rotary shaft and the rotary shaft may be coupled to thebutterfly valve by a nut member so that upon rotation of the shaft thenut member is driven back and forward in a linear direction to cause thebutterfly valve to move in a linear direction.

[0050] Since modifications within the spirit and scope of the inventionmay readily be effected by persons skilled within the art, it is to beunderstood that this invention is not limited to the particularembodiment described by way of example hereinabove.

1. An engine speed system for a vehicle having an engine, a fuel and airsupply system for supplying air and fuel to the vehicle, and driveractuable means for controlling the supply of air and fuel so as toenable the speed of the vehicle to be increased or decreased by thedriver of the vehicle, said system including; a valve unit forselectively allowing, preventing or reducing the supply of air and fuelto the engine; control means for moving the valve to alter the amount offuel and air supplied to the vehicle to thereby change the speed of thevehicle independent of the driver actuable means; receiver means forreceiving a transmitted signal to cause the control means to move thevalve unit for changing the speed of the engine independent of thedriver; and wherein the system includes a support member, the supportmember having an opening through which air and fuel can be supplied,said valve comprising a valve which is moveable in a linear manner so asto close the opening to a desired degree between a first positionallowing maximum supply of air and fuel to the engine and a secondposition allowing minimum or no supply of air or fuel to the engine. 2.The system of claim 1 wherein the control means comprises a steppermotor having a stepper motor shaft connected to the butterfly valve sothat upon actuation of the stepper motor the shaft is moved to in turnmove the butterfly valve between the fist and second positions.
 3. Thesystem of claim 1 wherein the receiving means. comprises a receiver andstepper motor controller for actuating the stepper motor to cause thebutterfly valve to move between the first and second positions.
 4. Thesystem of claim 1 wherein the system includes a transmitter fortransmitting the transmitted signal to the receiver for detection by thereceiver and for operating the stepper motor.
 5. The system of claim 1wherein the valve is a linearly moveable butterfly valve.
 6. The systemof claim 1 wherein the transmitter is coupled to a computer forreceiving operator inputs to cause the transmitter to transmit thetransmitted signal.
 7. A vehicle including; a fuel and air supply systemfor supplying air and fuel to the engine; a driver controlled throttlefor controlling the fuel and air supply system for altering the speed ofthe engine; a valve unit separate to the driver controlled throttle andnot operable by a driver of the vehicle for selectively allowing,preventing or reducing the supply of air and fuel to the engine; controlmeans for moving the valve to alter the amount of fuel and air suppliedto the vehicle to thereby change the speed of the vehicle independentlyof the driver; and receiver means for receiving a transmitted signal tocause the control means to move the valve for changing the speed of theengine independent of the driver.
 8. The vehicle of claim 7 wherein thefuel and air supply means comprises a carburettor including a primarybutterfly valve.
 9. The vehicle of claim 7 wherein the valve unitincludes a secondary butterfly valve.
 10. The vehicle of claim 7 whereinthe valve unit is a linearly moveable valve.
 11. A method of controllingthe speed of a vehicle on a driveway which is being driven by a driver,the method including the steps of; providing a vehicle with a driverthrottle control means operable by the driver to set the speed of thevehicle; providing a valve member in the vehicle independent of thedriver throttle control means and which is not operable by the driver,the valve member being actuable to adjust the speed of the vehicle;transmitting a signal to the vehicle from a remote location by way ofwireless transmission; and causing, by way of the transmission, theclosing of the valve member independent of driver control, so as toreduce, increase or shut off supply of air and fuel to a vehicle of theengine, and whereby, the speed of the engine is thereby altered by thetransmitted signal.